Problemn
Players can't rate or comment maps if they don't have 100 kills in approved matches, even if they are very experienced in the game and simply don't bother playing approved matches, i've seen this happen way too often.
Solution
The answer to this issue is already in the game, the 'new' levelling system could be used instead of the approved match kills to allow players to rate and comment maps, allowing players which are level 50 or above, maybe 100 or above, something like that.
This way players gain this ability just by playing the game however they want to play it but the 'experience' barrier is still there to avoid new players from judging maps without game knowledge.